The mag says a rep confirms that the actress, 41, is pregnant with her first child with financier Arpad Busson. Thurman has two children -- daughter Maya, 13, and son Levon, 10 -- with ex-husband Ethan Hawke.

People reports that Thurman and Busson, 49, began dating in 2007 and survived a brief split in 2009.

Life & Style magazine quotes a friend of the actress, who says, "She hasn't announced it yet, but a lot of her friends were asking her because they could tell the difference when they saw her at New York Fashion Week. She's usually so skinny, but now she has the cutest little bump and a glow about her."

Life & Style says Thurman "kept covered up" in the front row at the Tommy Hilfiger show on Feb. 12, wearing a baggy blouse and loose blazer.